Tuesday, 8 October 2013

A Chain of Cranes

A recent trip to the Daintree region, Cape Tribulation, north Queensland resulted in a walk during the day on the Marrdja Boardwalk. This should not be missed if visiting the area. It's a meandering track through forest and mangrove. It would be perfectly safe and convenient during rainy periods because it is elevated and has a combined rubber and wood surface so you won't slip or get muddy. You can see an assortment of mangrove biota including a variety of trees and shrubs and crabs and fish.

While most people were concentrating on Fiddler Crabs, fish and the like, I looked up and discovered chains of craneflies (family Tipulidae).
This is not the best photo I have ever taken but it shows three flies out of about 20 that were attached to one another by their tarsi. I saw a number of these chains and many were waving in the windy conditions making photography even more difficult. But what was the point? What were they doing?

Any comments?


Morgan Jackson said...

I think they may have been hanging from a spider web foundation line. I've heard of other nematocerans doing the same, whether because it's convenient or as a form of protection, I don't know. Very cool find & photo though!

Cece said...

I sent the picture to George Byers (University of Kansas, retired) and here is his response: "I don't know anything about the fauna of Queensland, but I'd almost bet they belong to the genus Dolichopeza, the flies I studied here in North America for my PhD. The flies suspend themselves with front legs, middle legs out to the side, hind legs (with some white on the tarsi) down and to the side, as in the photo. They can even hang from a spider web (cf. photo) and often occur in large numbers in shady places during the day)."

He didn't say what he thought they were doing - just hangin out, I guess.

Wong Chun Xing said...

I have observed this phenomenon many times here in Sabah. They just love to hang out like that in numbers. Sometimes they even fight and mate with each other while hanging and many of them died on the line, literally.

Anonymous said...

We walked this beautiful boardwalk just last week and loved it. Many orchids (not in bloom) and different tree species. The highlight was a pair of Little Kingfishers calling and flying about. Didn't see the Crane Flies, unfortunately.